Genome-Wide Characterization of ISR Induced in Arabidopsis thaliana by Trichoderma hamatum T382 Against Botrytis cinerea Infection.

In this study, the molecular basis of the induced systemic resistance (ISR) in Arabidopsis thaliana by the biocontrol fungus Trichoderma hamatum T382 against the phytopathogen Botrytis cinerea B05-10 was unraveled by microarray analysis both before (ISR-prime) and after (ISR-boost) additional pathogen inoculation. The observed high numbers of differentially expressed genes allowed us to classify them according to the biological pathways in which they are involved. By focusing on pathways instead of genes, a holistic picture of the mechanisms underlying ISR emerged.

Exploring the neutral invertase-oxidative stress defence connection in Arabidopsis thaliana.

Over the past decades, considerable advances have been made in understanding the crucial role and the regulation of sucrose metabolism in plants. Among the various sucrose-catabolizing enzymes, alkaline/neutral invertases (A/N-Invs) have long remained poorly studied. However, recent findings have demonstrated the presence of A/N-Invs in various organelles in addition to the cytosol, and their importance for plant development and stress tolerance.

Metabolism of galactosyl-oligosaccharides in Stellaria media--discovery of stellariose synthase, a novel type of galactosyltransferase.

The raffinose family oligosaccharides (RFOs), including raffinose (Gal-alpha(1-->6)-Glc-alpha(1-->2)beta-Fru), stachyose (Gal-alpha(1-->6)-Gal-alpha(1-->6)-Glc-alpha(1-->2)beta-Fru) and higher degree of polymerization RFOs are the most widespread galactosyl-oligosaccharides (GOS) in the plant kingdom. Stellaria media is a typical representative of the Caryophyllaceae, a plant family lacking stachyose and the typical galactosyl extensions of stachyose. During cold treatment raffinose, lychnose (Gal-alpha(1-->6)-Glc-alpha(1-->2)beta-Fru-alpha(1-->1)-Gal) and stellariose (Gal-alpha(1-->6)-[Gal-alpha(1-->4)]-Glc-alpha(1-->2)beta-Fru-alpha(1-->1)-Gal) were found to accumulate in S.

Isolation and characterization of a pentasaccharide from Stellaria media.

While classic raffinose family oligosaccharides (RFOs) such as raffinose and stachyose are common in plants, stachyose is absent in the Caryophyllaceae. Instead the tetrasaccharide lychnose α-d-Gal-(1→6)α-d-Glc-(1→2)β-d-Fru-(1→1)α-d-Gal can accumulate. Stellaria media, a representative member of this family, was used to isolate α-d-Gal-(1→6)-[α-d-Gal-(1→4)]α-d-Glc-(1→2)β-d-Fru-(1→1)α-d-Gal, a novel pentasaccharide with a lychnose backbone.

Complete NMR characterization of lychnose from Stellaria media (L.) Vill.

Lychnose (alpha-D-Gal-(1-->6)-alpha-D-Glc-(1-->2)-beta-D-Fru-(1-->1)-alpha-D-Gal) was isolated from Stellaria media, a representative member of the Caryophyllaceae plant family. Weak acid hydrolysis, enzymatic hydrolysis and complete NMR characterization were performed to confirm the identity of the tetrasaccharide. All (1)H and (13)C resonances were unambiguously assigned and the conformation of the sugars was determined using one and two dimensional NMR techniques.